java.util.HashSet int iteration order [duplicate]

Question

When i run the code which shown in below, the output is [50, 20, 5, 40, 10, 30]. I didn't understand this order. Why the output is not [10, 5, 20, 30, 40, 50] ?

List list = Arrays.asList(10, 5, 10, 20, 30, 40, 50);
System.out.println(new HashSet(list));

Answer 1

Docs says

This class implements the Set interface, backed by a hash table (actually a HashMap instance). It makes no guarantees as to the iteration order of the set; in particular, it does not guarantee that the order will remain constant over time. This class permits the null element.

go for LinkedHashSet

Answer 2

HashSet doesn't maintain insertion order. What you need is a LinkedHashSet.